diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 0321283b..0a7745de 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -14,7 +14,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
-      - uses: dtolnay/rust-toolchain@e814c742d4444ce2f3f6abddea7faf00161ed941 # 1.88.0
+      - uses: dtolnay/rust-toolchain@87eb139fed4b08a67bd1fa429a21d1f5d523e03e # 1.92.0
       - uses: Swatinem/rust-cache@e18b497796c12c097a38f9edb9d0641fb99eee32 # v2
       - run: cargo test --workspace --all-features --no-run
       - run: cargo test --workspace --all-features --no-fail-fast
@@ -25,7 +25,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
-      - uses: dtolnay/rust-toolchain@e814c742d4444ce2f3f6abddea7faf00161ed941 # 1.88.0
+      - uses: dtolnay/rust-toolchain@87eb139fed4b08a67bd1fa429a21d1f5d523e03e # 1.92.0
         with:
           components: clippy, rustfmt
       - uses: Swatinem/rust-cache@e18b497796c12c097a38f9edb9d0641fb99eee32 # v2
diff --git a/Cargo.toml b/Cargo.toml
index 527944ec..38686a18 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,7 +1,7 @@
 [package]
 name = "codex"
 version = "0.3.0"
-rust-version = "1.88" # also change in ci.yml
+rust-version = "1.92" # also change in ci.yml
 authors = ["The Typst Project Developers"]
 edition = "2024"
 description = "Human-friendly notation for Unicode symbols."
diff --git a/src/styling.rs b/src/styling.rs
index 822225bb..17055773 100644
--- a/src/styling.rs
+++ b/src/styling.rs
@@ -5,7 +5,7 @@ use std::iter::FusedIterator;
 
 /// The version of [Unicode](https://www.unicode.org/) that this version of the
 /// styling module is based on.
-pub const UNICODE_VERSION: (u8, u8, u8) = (17, 0, 0);
+pub const UNICODE_VERSION: (u8, u8, u8) = (18, 0, 0);
 
 /// A style for mathematical symbols.
 ///
@@ -67,7 +67,8 @@ pub enum MathStyle {
     Bold,
     /// Italic style. May be serif or sans-serif depending on the font.
     ///
-    /// Supported characters: latin, greek, dotless, and the extra ħ (U+0127).
+    /// Supported characters: latin, greek, dotless, and the extra ħ (U+0127)
+    /// and 𝾕 (U+1DF95).
     Italic,
     /// Bold italic style. May be serif or sans-serif depending on the font.
     ///
@@ -266,7 +267,7 @@ impl MathStyle {
             (_, true, None) if is_latin(c) | is_lower_greek(c) => MathStyle::BoldItalic,
             (_, true, None) if is_upper_greek(c) => MathStyle::Bold,
             (_, true, _) if is_digit(c) | matches!(c, 'Ϝ' | 'ϝ') => MathStyle::Bold,
-            (_, _, Some(true) | None) if matches!(c, 'ı' | 'ȷ' | 'ħ') => {
+            (_, _, Some(true) | None) if matches!(c, 'ı' | 'ȷ' | 'ħ' | '𝾕') => {
                 MathStyle::Italic
             }
             (_, _, Some(true) | None) if is_hebrew(c) => MathStyle::Hebrew,
@@ -413,7 +414,7 @@ pub fn to_style(c: char, style: MathStyle) -> ToStyle {
 /// All functions in this module expect that characters have been normalized
 /// through [`conversions::normalize`].
 ///
-/// [Unicode Core Specification - Section 22.2, Letterlike Symbols]: <https://www.unicode.org/versions/Unicode17.0.0/core-spec/chapter-22/#G14143>
+/// [Unicode Core Specification - Section 22.2, Letterlike Symbols]: <https://www.unicode.org/versions/Unicode18.0.0/core-spec/chapter-22/#G14143>
 /// [Letterlike Symbols]: <https://unicode.org/charts/PDF/U2100.pdf>
 /// [Mathematical Alphanumeric Symbols]: <https://unicode.org/charts/PDF/U1D400.pdf>
 /// [Arabic Mathematical Alphabetic Symbols]: <https://unicode.org/charts/PDF/U1EE00.pdf>
@@ -472,8 +473,8 @@ mod conversions {
 
     /// The character given by adding `delta` to the codepoint of `c`.
     #[inline]
-    fn apply_delta(c: char, delta: u32) -> char {
-        std::char::from_u32((c as u32) + delta).unwrap()
+    fn apply_delta(c: char, delta: i32) -> char {
+        std::char::from_u32((c as u32).strict_add_signed(delta)).unwrap()
     }
 
     pub fn to_bold(c: char) -> char {
@@ -519,6 +520,8 @@ mod conversions {
             // Dotless symbols (U+1D6A4..U+1D6A5)
             'ı' => 0x1D573,
             'ȷ' => 0x1D46E,
+            // Ligature long s (U+1D6A6)
+            '𝾕' => -0x8EF,
             // Italic Greek symbols (U+1D6E2..U+1D714)
             'Α'..='Ρ' => 0x1D351,
             'ϴ' => 0x1D2FF,
@@ -878,7 +881,7 @@ mod conversions {
             'Γ' => 0x1DAB,
             'Π' => 0x1D9F,
             // Double-struck large operator (U+2140)
-            '∑' => return '⅀', // delta is negative
+            '∑' => -0xD1, // delta is negative
 
             // Mathematical Alphanumeric Symbols Block (U+1D400..U+1D7FF)
             // Double-struck symbols (U+1D538..U+1D56B)